Three-dimensional image display device and three-dimensional image display method for displaying control menu in three-dimensional image

ABSTRACT

A three-dimensional content playback unit outputs to two or more image buffers a plurality of stereoscopic images of three-dimensional content, including a first parallax image and a second parallax image, resulting from viewing an object in a virtual three-dimensional space from different viewpoints. An interrupt request receiving unit receives an interrupt request requesting that a control menu be displayed. A control menu output unit overwrites, responsive to the acquisition of an interrupt request by the interrupt request receiving unit, a drawn image of an object in a three-dimensional space with an image of an object of the control menu drawn with parallax while moving the object of the control menu in the depth direction of the virtual three-dimensional space away from the viewpoint, regardless of the relative positions of the object of the control menu and the object in the three-dimensional space.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a three-dimensional image displaydevice and a three-dimensional image display method.

2. Description of the Related Art

Recently, the performance of consumer television is improving andthree-dimensional television sets capable of presenting stereoscopicimages with depth are becoming available to the public. Unlike theconventional television displaying two-dimensional images,three-dimensional television presents images with depth in theantero-posterior direction.

A menu for adjusting image quality using on-screen display (OSD) or amenu for a control system of three-dimensional television should bedisplayed superimposed in the stereoscopic images being played back. Theuser viewing the stereoscopic images should adjust the focus of the eyesin accordance with the depth of the images. This may strain the useradjusting the focus depending on the position where the control menu ispresented. In particular, the visibility of the control menu may becomepoor when the control menu is presented disregarding the relativepositions of the stereoscopic images in the three-dimensional space.

SUMMARY OF THE INVENTION

The present invention addresses this issue and a purpose thereof is toprovide a technology capable of improving the visibility of a controlmenu in three-dimensional television.

One embodiment of the present invention that addresses the issue is athree-dimensional image display device. The device comprises: athree-dimensional content playback unit configured to output to two ormore image buffers a plurality of stereoscopic images ofthree-dimensional content, including a first parallax image and a secondparallax image, resulting from viewing an object in a virtualthree-dimensional space from different viewpoints; an interrupt requestreceiving unit configured to receive an interrupt request requestingthat a control menu be displayed; and a control menu output unitconfigured to overwrite, responsive to the acquisition of an interruptrequest by the interrupt request receiving unit, a drawn image of anobject in a three-dimensional space with an image of an object of thecontrol menu drawn with parallax while moving the object of the controlmenu in the depth direction of the virtual three-dimensional space awayfrom the viewpoint, regardless of the relative positions of the objectof the control menu and the object in the three-dimensional space.

Another embodiment of the present invention is also a three-dimensionalimage display device. The device comprises: a three-dimensional contentplayback unit configured to output to two of more image buffers aplurality of stereoscopic images of three-dimensional content, includinga first parallax image and a second parallax image, resulting fromviewing an object in a virtual three-dimensional space from differentviewpoints; an interrupt request receiving unit configured to receive aninterrupt request requesting that a control menu be displayed; a bufferduplication unit configured to copy, responsive to the acquisition of aninterrupt request by the interrupt request receiving unit, content inthe image buffer storing either the first parallax image or the secondparallax image to the other image buffer; and a control menu output unitconfigured to overwrite, responsive to the acquisition of an interruptrequest by the interrupt request receiving unit, display areas for theobjects already drawn with an image of an object of the control menu,regardless of the relative positions of the object of the control menuand the object already drawn.

Still another embodiment of the present invention is also athree-dimensional image display device. The device comprises: athree-dimensional content playback unit configured to output to two ormore image buffers a plurality of stereoscopic images ofthree-dimensional content, including a first parallax image and a secondparallax image, resulting from viewing an object in a virtualthree-dimensional space from different viewpoints; an interrupt requestreceiving unit configured to receive an interrupt request requestingthat a control menu be displayed; a closest coordinate acquisition unitconfigured to acquire, responsive to the acquisition of an interruptrequest by the interrupt request receiving unit, positional coordinatesof the content located closest to the viewpoint in the virtualthree-dimensional space for all the three-dimensional content output bythe three-dimensional content playback unit; and a control menu outputunit configured to output to the image buffers, responsive to theacquisition of an interrupt request by the interrupt request receivingunit, an image of an object of the control menu located nearer to theviewpoint than the positional coordinates acquired by the closestcoordinate acquisition unit.

Another embodiment of the present invention is also a three-dimensionalimage display method. The method comprises: outputting to two or moreimage buffers a plurality of stereoscopic images of three-dimensionalcontent, including a first parallax image and a second parallax image,resulting from viewing an object in a virtual three-dimensional spacefrom different viewpoints; receiving an interrupt request requestingthat a control menu be displayed; and overwriting, responsive to theacquisition of an interrupt request, a drawn image of an object in athree-dimensional space with an image of an object of the control menudrawn with parallax while moving the object of the control menu in thedepth direction of the virtual three-dimensional space away from theviewpoint, regardless of the relative positions of the object of thecontrol menu and the object in the three-dimensional space.

Still another embodiment of the present invention is also athree-dimensional image display method. The method comprises: outputtingto two or more image buffers a plurality of stereoscopic images ofthree-dimensional content, including a first parallax image and a secondparallax image, resulting from viewing an object in a virtualthree-dimensional space from different viewpoints; receiving aninterrupt request requesting that a control menu be displayed; copying,responsive to the acquisition of an interrupt request, content in theimage buffer storing either the first parallax image or the secondparallax image to the other image buffer; and overwriting, responsive tothe acquisition of an interrupt request, display areas for the objectsalready drawn with an image of an object of the control menu, regardlessof the relative positions of the object of the control menu and theobject already drawn.

Yet another embodiment of the present invention is also athree-dimensional image display method. The method comprises: outputtingto two or more image buffers a plurality of stereoscopic images ofthree-dimensional content, including a first parallax image and a secondparallax image, resulting from viewing an object in a virtualthree-dimensional space from different viewpoints; receiving aninterrupt request requesting that a control menu be displayed; andacquiring, responsive to the acquisition of an interrupt request,positional coordinates of the content located closest to the viewpointin the virtual three-dimensional space for all three-dimensional contentoutput to the image buffers, and outputting to the image buffers animage of an object of the control menu located nearer to the viewpointthan the acquired positional coordinates.

Optional combinations of the aforementioned constituting elements, andimplementations of the invention in the form of methods, apparatuses,systems, recording mediums and computer programs may also be practicedas additional modes of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will now be described, by way of example only, withreference to the accompanying drawings which are meant to be exemplary,not limiting, and wherein like elements are numbered alike in severalFigures, in which:

FIG. 1 shows a relation between an object and parallax images in athree-dimension space;

FIG. 2 is a schematic view of a shutter-based three-dimensionaltelevision system in which parallax images are used;

FIG. 3 shows a relation between the timing of driving the shutter of theshutter glasses and the timing of displaying parallax images inthree-dimensional television;

FIG. 4 shows parameters necessary to compute parallax;

FIG. 5 shows the relative positions of an object of a control menu andanother object in a virtual three-dimensional space;

FIG. 6A shows how the object of the control menu is displayed dependingon its position relative to the other object;

FIG. 6B shows how the control menu is displayed in a three-dimensionalimage display device according to the first embodiment by way ofexample;

FIG. 7 schematically shows the functions of the three-dimensional imagedisplay device according to the first embodiment;

FIG. 8 is a flowchart showing the steps for displaying images performedin the three-dimensional image display device according to the firstembodiment;

FIG. 9 schematically shows the functions of the three-dimensional imagedisplay device according to the second embodiment;

FIG. 10A shows an example of a left-eye parallax image as displayed;

FIG. 10B shows an example of a right-eye parallax image as displayed;

FIG. 10C shows an example of a control menu presented to the left eye inthe three-dimensional image display device according to the secondembodiment;

FIG. 10D shows an example of a control menu presented to the left eye inthe three-dimensional image display device according to the secondembodiment;

FIG. 11 is a flowchart showing the steps for displaying images performedin three-dimensional image display according to the second embodiment;

FIG. 12 schematically shows the functions of the three-dimensional imagedisplay device according to the third embodiment;

FIG. 13A shows the relative positions of the object of the control menuand the other object in the three-dimensional space as displayed by thethree-dimensional image display device according to the thirdembodiment;

FIG. 13B shows an example of the control menu displayed in thethree-dimensional image display device according to the thirdembodiment; and

FIG. 14 is a flowchart showing the steps for displaying images performedin three-dimensional image display according to the third embodiment.

DETAILED DESCRIPTION OF THE INVENTION

The invention will now be described by reference to the preferredembodiments. This does not intend to limit the scope of the presentinvention, but to exemplify the invention.

A description will be given of a base technology before describing anembodiment of the present invention.

(Base Technology)

FIG. 1 shows a relation between an object and parallax images in athree-dimension space. In a three-dimensional space, an object 200 a, anobject 200 b, an object 200 c, which will be generically referred to asobjects 200, are imaged by a left-eye camera 202 a adapted to image theobject 200 from left and a right-eye camera 202 b adapted to image theobject 200 from right, which will be generically referred to as cameras202. Referring to FIG. 1, an image of the object 200 captured by theleft-eye camera 202 a and an image of the object 200 captured by theright-eye camera 202 b are displayed in a monitor 204 a and a monitor204 b, respectively, which will be generically referred to astwo-dimensional monitors 204.

The left-eye camera 202 a and the right-eye camera 202 b image theobject 200 from different positions. Therefore, the image displayed onthe monitor 204 a and the image displayed on the monitor 204 b show theobject 200 oriented in different directions. Images of the object 200 ina three-dimensional space as viewed from different viewpoints arereferred to as “parallax images”. Since human eyes are spaced apart byabout 10 cm, parallax is produced between an image viewed from the lefteye and an image viewed from the right eye. Human brain is said torecognize the depth of an object using parallax images perceived by theleft and right eyes. For this reason, by projecting a parallax imageperceived by the left eye and a parallax image perceived by the righteye to the respective eyes, an image having a depth is perceived by aperson.

Various methods are used to implement three-dimensional television forpresenting an image with depth to people. In this embodiment, adescription will be given of shutter-based three-dimensional televisionalternately displaying a parallax image for the left eye and a parallaximage for the right eye in a time-divided manner. FIG. 2 is a schematicview of a shutter-based three-dimensional television system 300utilizing parallax images. The three-dimensional television system 300comprises a three-dimensional television 206 for projecting parallaximages, shutter glasses 210 used to view parallax images, and a glassdriving signal origination unit 208 for synchronizing thethree-dimensional television 206 and the shutter glasses 210.

The three-dimensional television 206 alternately presents the left-eyeparallax image and the right-eye parallax image in a time-divisionmanner. The glass driving signal origination unit 208 originates aninfrared synchronization signal indicating the timing of display of theparallax images in the three-dimensional television 206. The shutterglasses 210 is provided with a receiver (not shown) for receiving asynchronizing signal transmitted from the glass driving signalorigination unit 208 and shutters the left or right lens in accordancewith the received synchronizing signal. The shutter is implemented byusing the known technology of liquid crystal shutters.

More specifically, when the three-dimensional television 206 displays aleft-eye parallax image, the shutter glasses 210 receive a signal forclosing the shutter of the right eye lens from the glass driving signalorigination unit 208. The shutter glasses 210 shield an image enteringthe right eye by closing the shutter of the right eye lens in accordancewith the received signal. This results in only the left-eye parallaximage being projected to the left eye of the user when thethree-dimensional television 206 displays the left-eye parallax image.Conversely, when the three-dimensional television 206 displays theright-eye parallax image, only the right-eye parallax image is projectedto the right eye of the user by allowing the shutter glasses 210 toclose the shutter of the left eye lens.

FIG. 3 shows a relation between the timing of driving the shutter of theshutter glasses 210 and the timing of displaying parallax images in thethree-dimensional television 206. A left-eye parallax image 212 a, aleft-eye parallax image 212 b, a left-eye parallax image 212 c, whichare generically referred to as left-eye parallax images 212, and aright-eye parallax image 214 a, a right-eye parallax image 214 b, and aright-eye parallax image 214 c, which are generically referred to asright-eye parallax images 214, are alternately displayed at apredetermined interval t (e.g., 1/120 sec).

When the left-eye parallax image 212 a is being displayed, the left-eyeshutter of the shutter glasses 210 is open and the right-eye shutter isclosed. Referring to FIG. 3, the open state of the shutter of theshutter glasses 210 is indicated by “O” and the closed state isindicated by “X”. As shown in FIG. 3, three-dimensional images withdepth are presented to the user by synchronizing the display of parallaximages in the three-dimensional television 206 and the opening/closingof the shutter glasses 210 such that the left-eye parallax images 212are projected to the left eye of the user and the right-eye parallaximages 214 are projected to the right eye.

FIG. 4 shows parameters necessary to compute parallax. Given a virtualthree-dimensional space displayed by the three-dimensional television206 (hereinafter, simply referred to as “three-dimensional space”), acoordinate system is defined using an arbitrary point in the displayscreen of the three-dimensional television 206 (e.g., the bottom rightpoint in the display screen of the three-dimensional television 206 asinstalled) as the original, the transversal direction of the displayscreen as the x-axis, and the vertical direction as the y-axis, and thedirection perpendicular to the display screen of the three-dimensionaltelevision 206 as the z-axis. FIG. 4 shows the three-dimensional spacedisplayed by the three-dimensional television 206 viewed in a directionparallel with the y-axis.

Parallax X that should be reflected in the display screen of thethree-dimensional television 206 is computed based on the z coordinate Wof the object 200 in the three-dimensional space. Parameters necessaryto compute parallax include a distance D in the three-dimensional spacebetween the left-eye camera 202 a or the right-eye camera 202 b and thedisplay screen, an average value e of the space between human eyes, anda size of the display screen of the three-dimensional television 206. Itis assumed that the left-eye camera 202 a and the right-eye camera 202 bare located at positions in the three-dimensional space spaced apart bythe average value e of the space between human eyes.

Using the parameters noted above, the ratio between the z-coordinate Wof the object 200 in the three-dimensional space and the distance D inthe three-dimensional space between the camera 202 and the displayscreen are computed. Parallax X on the display screen of thethree-dimensional television 206 is computed based on the ratio and theaverage value e between human eyes. Finally, parallax X is convertedinto the unit of the coordinate system in the three-dimensional spacebased on the size of the display screen of the three-dimensionaltelevision 206. It is ensured that parallax is zero when the object 200is located on the display screen of the three-dimensional television206. In this case, the left-eye parallax image and the right-eyeparallax image of the object 200 located on the display screen of thethree-dimensional television 206 are identical.

With the technology described above as the basis, a description will nowbe given of the embodiment.

The embodiment relates to a method of displaying the system's controlmenu for playing back content while content including three-dimensionalimages of games or movies are being played back in the three-dimensionaltelevision 206. The term “control menu” denotes information presented tothe user by the system program for centrally controlling a device forplaying back content and running an application program such as content.For example, a control menu includes information not related to thecontent played back but related to the operation of the playback device.For example, the menu allows selection of whether the playback of thecontent should be stopped or not, gives an alert indicating that thefree space in a memory card is insufficient for the user to save gamecontent, gives an alert indicating that the remaining battery power islow in the case that the playback device is of mobile type operated by abuilt-in battery.

First Embodiment

A summary of the first embodiment will be described. In the firstembodiment, a control menu is displayed while content includingthree-dimensional images of games or movies are being played back in thethree-dimensional television 206 such that an object of a control menuis defined in the three-dimensional space and is drawn while moving theobject away from the viewpoint in the depth direction. In the eyes ofthe user, it looks as if the system menu comes entering thethree-dimensional space moving away from the user.

FIG. 5 shows the relative positions of an object 216 of the control menuand the other object 200 in the three-dimensional space. As shown inFIG. 5, an object 216 a of the control menu, which could be one ofobjects generically referred to as objects 216 of the control menu,appears more toward the viewpoint in the three-dimensional space thanthe object 200, moving in the direction of sight until it reaches theposition of an object 216 b of the control menu. The relative positionsof the object 216 b of the control menu and the other object 200 asviewed from the camera 202 placed at the viewpoint in thethree-dimensional space is such that the object 200 is located moretoward the viewpoint.

FIG. 6A shows how the object 216 b of the control menu is displayeddepending on its position relative to the other object 200. Since theobject 216 b of the control menu is located behind the other object 200as viewed from the camera 202, the object 216 b of the control menu ishidden by the object 200.

As described above, the control menu is often used to present importantinformation related to the operation of the device for playing backcontent to the user. Therefore, disadvantage may be caused if the object216 b of the control menu is shielded from view by being hidden by theobject 200. The first embodiment addresses this disadvantage byoverwriting the image of the other object 200 with the object 216 of thecontrol menu irrespective of the relative positions of the object 216 ofthe control menu and the other object 200.

FIG. 6B shows how the control menu is displayed in a three-dimensionalimage display device 100 according to the first embodiment by way ofexample. Even if the object 216 a of the control menu appears moretoward the viewpoint in the three-dimensional space than the object 200and moves behind the object 200, the object 200 is overwritten with theobject 216 of the control menu. This allows the user to view the object216 of the control menu irrespective of its position relative to theother object 200.

When the object 216 of the control menu is drawn regardless of therelative positions of the object 216 and the other object 200 in thethree-dimensional space, the user may feel uneasy viewing the objects.As shown in FIG. 5 and FIGS. 6A-6B, the user may feel as if the camera202 capturing the image of the other object 200 is pulled toward theuser, by displaying the object 216 of the control menu toward the camera202, which represents the viewpoint, and then moving the object 216 inthe direction of sight. This illusion helps reduce the uneasiness feltby the viewing user even if the relative positions of the object 216 ofthe control menu and the other object 200 is not accurately displayed.

The position of appearance of the object 216 a of the control menu maybe experimentally determined so as to reduce the uneasiness in viewing.By moving the object 216 b of the control menu to the position alignedwith the display screen of the three-dimensional television 206 as shownin FIG. 5, the user can view the control menu clearly without wearingthe shutter glasses 210. This is because the left-eye parallax image andthe right-eye parallax image of the object 216 b of the control menuwill be identical if the object 216 b is located on the display screenof the three-dimensional television 206.

FIG. 7 schematically shows the functions of the three-dimensional imagedisplay device 100 according to the first embodiment. Thethree-dimensional image display device 100 according to the firstembodiment comprises a three-dimensional content playback unit 10, aninterrupt request receiving unit 12, a luminance value control unit 14,a control menu output unit 16, and an image buffer 18.

The three-dimensional content playback unit 10 outputs to the imagebuffer 18 stereoscopic images of three-dimensional content (hereinafter,referred to as “stereoscopic images”) including the left-eye parallaximage and the right-eye parallax image resulting from viewing an objectin the three-dimensional space from different viewpoints. Therefore, theimage buffer 18 includes a left-eye buffer 26 and a right-eye buffer 28.The left-eye buffer 26 stores the left-eye parallax image and theright-eye buffer 28 stores the right-eye parallax image. The parallaximages stored in the left-eye buffer 26 and the right-eye buffer 28 areread by an image drawing unit of the three-dimensional television 206and alternately displayed on the display screen of the three-dimensionaltelevision 206 as described above.

The interrupt request receiving unit 12 receives an interrupt requestrequesting that a control menu be displayed. For example, an interruptrequest is generated when the user presses a predetermined button of thecontroller (not shown) of the three-dimensional image display device 100or generated by the operating system run in the three-dimensional imagedisplay device 100 when the free space in the memory card isinsufficient.

Responsive to the acquisition of an interrupt request by the interruptrequest receiving unit 12, the control menu output unit 16 overwritesthe image of the other object 200 in the three-dimensional space storedin the buffer 18 with the object 216 of the control menu, while movingthe object 216 away from the viewpoint in the three-dimensional space inthe depth direction, irrespective of the relative positions of theobject 216 and the other object in the three-dimensional space. For thispurpose, the control menu output unit 16 comprises a stereoscopic imagegeneration control unit 20, a parallax acquisition unit 22, and athree-dimensional computer graphics (CG) acquisition unit 24.

The stereoscopic image generation control unit 20 places the object 216of the control menu in the three-dimensional space, as shown in FIG. 5and FIGS. 6A-6B. The parallax acquisition unit 20 computes the parallaxassociated with the object 216 of the control menu in thethree-dimensional space occurring when the object 216 is viewed from theleft-eye camera 202 a and the right-eye camera 202 b placed in thethree-dimensional space. Based on the parallax acquired by the parallaxacquisition unit 22, the three-dimensional CG acquisition unit 24projects the object 216 of the control menu in the three-dimensionalspace so as to generate a two-dimensional buffer, overwriting the imagebuffer 18 accordingly.

Responsive to the acquisition of an interrupt request by the interruptrequest receiving unit 12, the luminance value control unit 14 lowersthe luminance value of the stereoscopic images other than the object 216of the control menu. More specifically, the unit 14 lowers the luminancevalues of the parallax images output by the three-dimensional contentplayback unit 10 to half and stores the values in the image buffer 18.In combination with the aforementioned illusion produced by moving theobject 216 away from the viewpoint so that it looks as if the camera 202imaging the object is pulled toward the user, reduction in luminancefurther reduces the uneasiness felt by the viewing user as a result ofdisregarding the relative positions. This is advantageous in enhancingthe visibility of the control menu relative to other stereoscopicimages.

The three-dimensional content playback unit 10 may suspend the playbackof content responsive to the acquisition of an interrupt request by theinterrupt request receiving unit 12. This advantageous in thatuneasiness felt by the viewing user is further reduced since only thecontrol menu is moved.

FIG. 7 shows functional components to implement the three-dimensionalimage display device 100 according to the first embodiment and the othercomponents are omitted. The elements depicted in FIG. 7, etc. asfunctional blocks for performing various processes are implemented inhardware by a CPU, main memory, or other LSI's (large-scale intergrationcircuits), and in software by a program etc., loaded into the mainmemory. Therefore, it will be obvious to those skilled in the art thatthe functional blocks may be implemented in a variety of manners byhardware only, software only, or a combination of thereof.

FIG. 8 is a flowchart showing the steps for displaying images performedin the three-dimensional image display device 100 according to the firstembodiment. Referring to the flowchart, each step performed is denotedby a combination of S (initial letter of Step), which indicates “step”,and a numeral. When a determination is performed in a step denoted by acombination of S and a numeral and when the result of determination isaffirmative, Y (initial letter of Yes) is used to indicate theaffirmative determination (e.g., Y in S12). Conversely, when the resultof determination is negative, N (initial letter of No) is used toindicate the negative determination (e.g., N in S12). The steps in theflowchart are started when the three-dimensional content playback unit10 starts playing back stereoscopic images.

The three-dimensional content playback unit 10 plays back stereoscopicimages of three-dimensional content (S10). When the interrupt requestreceiving unit 12 does not receive an interrupt request (N in S12),three-dimensional content playback unit 10 continues to play backstereoscopic images. When the interrupt request receiving unit 12receives an interrupt request (Y in S12), the luminance value controlunit 14 suppresses the luminance value of the stereoscopic images otherthan the object 216 of the control menu (S14).

The stereoscopic image generation control unit 20 initializes the depthof the object 216 of the control menu, by placing the object at theposition of the object 216 a of the control menu shown in FIGS. 5 and6A-6B (S16). The parallax acquisition unit 22 computes and acquires theparallax associated with the object 216 of the control menu in thethree-dimensional space occurring when the object 216 is viewed from theleft-eye camera 202 a and the right-eye camera 202 b placed in thethree-dimensional space (S18). The three-dimensional CG acquisition unit24 projects the object 216 of the control menu in the three-dimensionalspace based on the parallax acquired by the parallax acquisition unit 22and generates parallax images accordingly (S20). The three-dimensionalCG acquisition unit 24 overwrite the buffer 18 with the generatedparallax images of the control menu and outputs the content of thebuffer (S22).

The stereoscopic image generation control unit 20 moves the object 216of the control menu in the three-dimensional space by a predetermineddistance in the direction of sight and updates the depth informationaccordingly (S24). For example, the predetermined distance is defined asa distance obtained by dividing the space between the object 216 a ofthe control menu and the object 216 b of the control menu, which areshown in FIGS. 5 and 6A-6B, by ten.

While the object 216 of the control menu has not reached the position onthe display screen of the three-dimensional television 206 (N in S26),the steps for generating parallax images of the control menu (steps S18through S24 described above) are repeated. When the object 216 of thecontrol menu reaches the position on the display screen of thethree-dimensional television 206 (Y in S26) as a result of updating ofthe position of the object 216 of the control menu performed by thestereoscopic image generation control unit 20, the process according tothe flowchart is terminated.

The device with the configuration described above operates as follows.The user plays back stereoscopic images using the three-dimensionalimage display device 100 according to the first embodiment. When theinterrupt request receiving unit 12 acquires an interrupt request (e.g.,the user's request to suspend the playback of content), the control unitoutput unit 16 displays the control menu, moving the menu away in thedepth direction of the three-dimensional space.

As described above, according to the first embodiment, the user can viewthe control menu at any time by overwriting the other object 200 withthe control menu and displaying the menu accordingly. By displaying thecontrol menu such that the menu moves away in the depth direction of thethree-dimensional space, resultant illusion helps improve the visibilityof the control menu even if the control menu is displayed regardless ofthe relative positions of the object 216 of the control menu and theother object 200. By ultimately displaying the control menu at theposition, in the three-dimensional space, on the display screen of thethree-dimensional television 206, the user can clearly view the controlmenu without wearing the shutter glasses 210.

Second Embodiment

A summary of the second embodiment will be described. According to thesecond embodiment, a control menu is displayed while thethree-dimensional television 206 is playing back content that includestereoscopic images of games and movies such that the right-eye parallaximage is replaced by the left-eye parallax image and displayedaccordingly. The displayed image is then overwritten with the controlmenu and the resultant image is displayed. The user experiences noparallax between the images entering the left and right eyes. Therefore,the visibility of the image as a whole, including the control menu, isimproved.

FIG. 9 schematically shows the functions of the three-dimensional imagedisplay device 100 according to the second embodiment. Thethree-dimensional image display device according to the secondembodiment comprises a three-dimensional content playback unit 10, aninterrupt request receiving unit 12, a luminance value control unit 14,a buffer duplication unit 30, a control menu output unit 16, and animage buffer 18. The image buffer 18 includes a left-eye buffer 26 and aright-eye buffer 28. Hereinafter, description of those aspects of thesecond embodiment that are also found in the first embodiment will beomitted.

Responsive to the acquisition of an interrupt request by the interruptrequest receiving unit 12, the buffer duplication unit 30 overwrites theleft-eye parallax image stored in the right-eye buffer 26 with theright-eye parallax image stored in the left-eye buffer 28 usingduplication. Responsive to the acquisition of an interrupt request bythe interrupt request receiving unit 12, the control menu output unit 16overwrites display areas in the left-eye buffer 26 and the right-eyebuffer 28 storing the left-eye parallax image with the image of theobject 216 of the control menu.

FIG. 9 shows functional components to implement the three-dimensionalimage display device 100 according to the second embodiment and theother components are omitted. The elements depicted in FIG. 9, etc. asfunctional blocks for performing various processes are implemented inhardware by a CPU, main memory, or other LSI's, and in software by aprogram etc., loaded into the main memory. Therefore, it will be obviousto those skilled in the art that the functional blocks may beimplemented in a variety of manners by hardware only, software only, ora combination of thereof.

FIG. 10A shows an example of a left-eye parallax image stored in theleft-eye buffer 26. FIG. 10B shows an example of a right-eye parallaximage stored in the right-eye buffer 28. As shown in FIGS. 10A and 10B,before the interrupt request receiving unit 12 receives an interruptrequest, the left-eye parallax image and the right-eye parallax imageare images resulting from viewing an object from different angles.

When the interrupt request receiving unit 12 receives an interruptrequest, the buffer duplication unit 30 overwrites the right-eyeparallax image stored in the right-eye buffer 28 with the left-eyeparallax image stored in the left-eye buffer 26. The control menu outputunit 16 overwrites display areas in the left-eye buffer 26 and theright-eye buffer 28 with the image of the object 216 of the controlmenu.

FIG. 10C shows an example of a control menu presented to the left eye inthe three-dimensional image display device 100 according to the secondembodiment. FIG. 10D shows an example of a control menu presented to theright eye in the three-dimensional image display device 100 according tothe second embodiment. As shown in FIGS. 10A and 10B, the left-eyeparallax image stored in the left-eye buffer 26 and the right-eyeparallax image stored in the right-eye buffer 28 are identical.

As a result of the buffer duplication 30 overwriting the right-eyeparallax image stored in the right-eye buffer 28 with the left-eyeparallax image stored in the left-eye buffer 26, the left-eye parallaximage is projected to the left and right eyes of the user. For thisreason, an ordinary two-dimensional image with depth information lost ispresented to the eyes of the user. When an ordinary two-dimensionalimage with no depth information is overwritten with the control menu,the visibility of the control menu is advantageously improved ascompared to the case where a stereoscopic image with depth isoverwritten at a certain position with the control menu since the userdoes not have to adjust the focus of the eyes. In this case, the usercan clearly view the entirety of the image, including the control menu,without wearing the shutter glasses 210.

In the above description, it is assumed that the buffer duplication unit30 overwrites the right-eye parallax image stored in the right-eyebuffer 28 with the left-eye parallax image stored in the left-eye buffer26. Alternatively, the buffer duplication unit 30 may overwrite theleft-eye parallax image stored in the left-eye buffer 26 with theright-eye parallax image stored in the right-buffer 28. Either approachserves the purpose so long as the images projected to the eyes of theuser are identical. What is essential is that the image stored in one ofthe image buffers in the image buffer 18 is copied to the other imagebuffer.

FIG. 11 is a flowchart showing the steps for displaying images performedin the three-dimensional image display device 100 according to thesecond embodiment. The steps in the flowchart are started when thethree-dimensional content playback unit 10 starts playing backstereoscopic images.

The three-dimensional content playback unit 10 plays back stereoscopicimages of three-dimensional content (S10). When the interrupt requestreceiving unit 12 does not receive an interrupt request (N in S12),three-dimensional content playback unit 10 continues to play backstereoscopic images. When the interrupt request receiving unit 12receives an interrupt request (Y in S12), the luminance value controlunit 14 suppresses the luminance value of the stereoscopic images otherthan the object 216 of the control menu (S14).

The buffer duplication unit 30 overwrites the right-eye parallax imagestored in the right-eye buffer 28 with the left-eye parallax imagestored in the left-eye buffer 26 using duplication (S30). The controlmenu output unit 16 displays the control menu by overwriting displayareas in the left-eye buffer 26 and the right-eye buffer 28 with theimage of the object 216 of the control menu (S32). When the control menuoutput unit 16 outputs the control menu, the process according to theflowchart is terminated.

The device with the configuration described above operates as follows.The user plays back stereoscopic images using the three-dimensionalimage display device 100 according to the second embodiment. When theinterrupt request receiving unit 12 acquires an interrupt request (e.g.,the user's request to suspend the playback of content), parallax-freeimages are presented to the user as a result of the buffer duplication30 overwriting the right-eye parallax image stored in the right-eyebuffer 28 with the left-eye parallax image stored in the left-eye buffer26 using duplication. The control menu output unit 16 further overwritesthe parallax-free images with the control menu.

As described above, according to the second embodiment, parallax betweenthe left-eye image and the right-eye image presented to the user iseliminated so that the visibility of the control menu is improved.Further, the user can clearly view the control menu without wearing theshutter glasses 210.

Third Embodiment

A summary of the third embodiment will be described. According to thethird embodiment, a control menu is displayed while thethree-dimensional television 206 is playing back content that includestereoscopic images of games and movies such that the depth of thecontent being played back is acquired so that the control menu isdisplayed more toward the viewpoint than the content located closest tothe viewpoint. Since this creates no inconsistency between position ofthe object 216 of the control menu and that of the object 200 as theyare displayed in the three-dimensional space, the user viewing thecontrol menu does not feel uneasy.

FIG. 12 schematically shows the functions of the three-dimensional imagedisplay device 100 according to the third embodiment. Thethree-dimensional image display device according to the third embodimentcomprises a three-dimensional content playback unit 10, an interruptrequest receiving unit 12, a luminance value control unit 14, a closestcoordinate acquisition unit 32, a depth buffer 34, a control menu outputunit 16, and an image buffer 18. The image buffer 18 includes a left-eyebuffer 26 and a right-eye buffer 28. Hereinafter, description of thoseaspects of the third embodiment that are also found in the first andsecond embodiments will be omitted.

The depth buffer 34 acquires and stores depth information ofstereoscopic images being played back from the three-dimensional contentplayback unit 10. The term “depth information of stereoscopic images”refers to the coordinate in the depth direction of the three-dimensionalspace corresponding to the pixels in a two-dimensional image produced byprojecting the object 200 placed in the three-dimensional space. Morespecifically, the information represents the coordinate in the z axis inFIG. 4 corresponding to each pixel in the two-dimensional image.

For this reason, a depth buffer may be called “z buffer”.

Responsive to the acquisition of an interrupt request by the interruptrequest receiving unit 12, the closest coordinate acquisition unit 32refers to the depth buffer 34 and acquires the positional coordinates ofthe object 200 located closest to the viewpoint in the three-dimensionalspace (hereinafter, referred to as “closest spot coordinate”), of allthe objects 200 in the three-dimensional content output by thethree-dimensional content playback unit 10.

Responsive to the acquisition of an interrupt request by the interruptrequest receiving unit 12, the control menu output unit 16 outputs theimage of the object 216 more toward the viewpoint than the closest spotcoordinate acquired by the closest coordinate acquisition unit 32.

FIG. 12 shows functional components to implement the three-dimensionalimage display device 100 according to the third embodiment and the othercomponents are omitted. The elements depicted in FIG. 12, etc. asfunctional blocks for performing various processes are implemented inhardware by a CPU, main memory, or other LSI's, and in software by aprogram etc., loaded into the main memory. Therefore, it will be obviousto those skilled in the art that the functional blocks may beimplemented in a variety of manners by hardware only, software only, ora combination of thereof.

FIG. 13A shows the relative positions of the object 216 of the controlmenu and the other object 200 in the three-dimensional space asdisplayed in the three-dimensional image display device 100 according tothe third embodiment.

Responsive to the acquisition of an interrupt request by the interruptrequest receiving unit 12, the closest coordinate acquisition unit 32refers to the depth buffer 34 storing the depth information on theobject 200 located in the three-dimensional space so as to acquire theclosest spot coordinate (coordinate M in FIG. 13A). Responsive to theacquisition of an interrupt request by the interrupt request receivingunit 12, the control menu output unit 16 outputs to the image buffer 18the image of the object 216 of the control menu located more toward theviewpoint, i.e., at a coordinate M+a in FIG. 13A, than the closest spotcoordinate M.

FIG. 13B shows an example of the control menu displayed in thethree-dimensional image display device 100 according to the thirdembodiment. As shown in FIG. 13A, the object 216 of the control menu islocated more toward the viewpoint than the object 200 so that the imageof the object 216 of the control menu is displayed closest to theviewpoint.

FIG. 14 is a flowchart showing the steps for displaying images performedin three-dimensional image display according to the third embodiment.The steps in the flowchart are started when the three-dimensionalcontent playback unit 10 starts playing back stereoscopic images.

The three-dimensional content playback unit 10 plays back stereoscopicimages of three-dimensional content (S10). When the interrupt requestreceiving unit 12 does not receive an interrupt request (N in S12),three-dimensional content playback unit 10 continues to play backstereoscopic images. When the interrupt request receiving unit 12receives an interrupt request (Y in S12), the luminance value controlunit 14 controls the luminance value of the stereoscopic images otherthan the image of the object 216 of the control menu (S14).

The closest coordinate acquisition unit 32 refers to the depth buffer 34so as to acquire the closest spot coordinate (S34). The control menuoutput unit 16 outputs to the image buffer 18 the image of the object216 of the control menu located more toward the viewpoint than theclosest spot coordinate acquired by the closest coordinate acquisitionunit 32 (S36).

The device with the configuration described above operates as follows.The user plays back stereoscopic images using the three-dimensionaldisplay device 100 according to the third embodiment. Responsive to theacquisition of an interrupt request by the interrupt request receivingunit 12 (e.g., the user's request to suspend the playback of content),the closest coordinate acquisition unit 32 refers to the depth buffer 34so as to acquire the closest spot coordinate, and the control menuoutput unit 16 outputs to the image buffer 18 the image of the controlmenu located more toward the viewpoint than the closest spot coordinate.

Since the control menu is presented at a position closest to theviewpoint in the three-dimensional space as viewed by the user accordingto the third embodiment, there will be no inconsistency between therelative positions in the three-dimensional space so that the visibilityof the control menu is improved.

The first through third embodiments are described above. Arbitrarycombinations of the embodiments will also be useful.

For example, the second embodiment may be combined with the firstembodiment or the third embodiment, and, further, the shutter glasses210 may be provided with a sensor (not shown) for detecting whether theglasses are worn. An advantage provided by this configuration, inaddition to the advantages of the first and third embodiment, is thatimages that depend on whether the shutter glasses 210 are worn can bepresented, by using identical left and right parallax images in responseto the removal of the shutter glasses 210 by the user. In other words,stereoscopic images are played back by projecting appropriate parallaximages to the left and right eyes of the user while the user is wearingthe shutter glasses 210. When the user is not wearing the shutterglasses 210, parallax-free images are presented to the user.

Described above is an explanation based on an exemplary embodiment. Theembodiment is intended to be illustrative only and it will be obvious tothose skilled in the art that various modifications to constitutingelements and processes could be developed and that such modificationsare also within the scope of the present invention.

While the embodiments described above assumes the use of a shutter toachieve three-dimensional television, any method to achievethree-dimensional television (e.g., a method using polarization or amethod using a head-mount display) may be used.

What is claimed is:
 1. A three-dimensional image display devicecomprising: a three-dimensional content playback unit configured tooutput to two or more image buffers a plurality of stereoscopic imagesof three-dimensional content, including a first parallax image and asecond parallax image, resulting from viewing an object as athree-dimensional (3D) object in a virtual three-dimensional space fromdifferent viewpoints, wherein a plurality of 3D objects are displayed inthe virtual three-dimensional space at various depths in a depthdirection from a viewpoint of a user; an interrupt request receivingunit configured to receive an interrupt request requesting that acontrol menu be displayed; and a control menu output unit configured todisplay the control menu stereoscopically as a 3D menu object withparallax and to dynamically move the 3D menu object away from theviewpoint of the user in the depth direction after receiving theinterrupt request, wherein, as the 3D menu object fluidly moves awayfrom the viewpoint, if any 3D object is located in front of the 3D menuobject in the depth direction, any portion of the 3D object overlappingwith the 3D menu object is overwritten by the 3D menu object, if any 3Dobject is located at a same depth of the 3D menu object in the depthdirection, any portion of the 3D object overlapping with the 3D menuobject is overwritten by the 3D menu object, and if any 3D object islocated behind the 3D menu object in the depth direction, any portion ofthe 3D object overlapping with the 3D menu object is overwritten by the3D menu object, wherein the user cannot interact with the 3D menu objectuntil it arrives at a final location in the virtual three-dimensionalspace, wherein the virtual three-dimensional space is defined such thata plane, where there is no parallax between the first parallax image andthe second parallax image, coincides with a display screen of thedisplay device displaying the image, and the control menu output unitoutputs the image of the menu object of the control menu drawn withparallax while moving the object of the control menu from a viewpointthat is nearer than the plane, where there is no parallax between thefirst parallax image and the second parallax image, until the objectreaches the plane and the menu object is displayed with no parallax atthe final location.
 2. The three-dimensional image display deviceaccording to claim 1, further comprising: a luminance value control unitconfigured to lower a luminance value of the stereoscopic images of thethree-dimensional content in response to the acquisition of an interruptrequest by the interrupt request receiving unit.
 3. A three-dimensionalimage display method comprising: outputting to two or more image buffersa plurality of stereoscopic images of three-dimensional content,including a first parallax image and a second parallax image, resultingfrom viewing an object as a three-dimensional (3D) object in a virtualthree-dimensional space from different viewpoints, wherein a pluralityof 3D objects are displayed in the virtual three-dimensional space atvarious depths in a depth direction from a viewpoint of a user on adisplay device; receiving an interrupt request requesting that a controlmenu be displayed; and displaying the control menu stereoscopically as a3D menu object with parallax and dynamically moving the 3D menu objectaway from the viewpoint of the user in the depth direction afterreceiving the interrupt request, wherein, as the 3D menu object fluidlymoves away from the viewpoint, if any 3D object is located in front ofthe 3D menu object in the depth direction, any portion of the 3D objectoverlapping with the 3D menu object is overwritten by the 3D menuobject, if any 3D object is located at a same depth of the 3D menuobject in the depth direction, any portion of the 3D object overlappingwith the 3D menu object is overwritten by the 3D menu object, and if any3D object is located behind the 3D menu object in the depth direction,any portion of the 3D object overlapping with the 3D menu object isoverwritten by the 3D menu object, wherein a user cannot interact withthe 3D menu object until it arrives at a final location in the virtualthree-dimensional space, and wherein the virtual three-dimensional spaceis defined such that a plane, where there is no parallax between thefirst parallax image and the second parallax image, coincides with adisplay screen of the display device displaying the image, outputtingthe image of the menu object of the control menu drawn with parallaxwhile moving the object of the control menu from a viewpoint that isnearer than the plane, where there is no parallax between the firstparallax image and the second parallax image, until the object reachesthe plane and the menu object is displayed with no parallax at the finallocation.
 4. A non-transitory computer readable medium having storedthereon a program, the program comprising: a module configured to outputto two or more image buffers a plurality of stereoscopic images ofthree-dimensional content, including a first parallax image and a secondparallax image, resulting from viewing an object as a three-dimensional(3D) object in a virtual three-dimensional space from differentviewpoints on a display device, wherein a plurality of 3D objects aredisplayed in the virtual three-dimensional space at various depths in adepth direction from a viewpoint of a user; a module configured toreceive an interrupt request requesting that a control menu bedisplayed; and a module configured to display the control menustereoscopically as a 3D menu object with parallax and to dynamicallymove the 3D menu object away from the viewpoint of the user in the depthdirection after receiving the interrupt request, wherein, as the 3D menuobject fluidly moves away from the viewpoint, if any 3D object islocated in front of the 3D menu object in the depth direction, anyportion of the 3D object overlapping with the 3D menu object isoverwritten by the 3D menu object, if any 3D object is located at a samedepth of the 3D menu object in the depth direction, any portion of the3D object overlapping with the 3D menu object is overwritten by the 3Dmenu object, and if any 3D object is located behind the 3D menu objectin the depth direction, any portion of the 3D object overlapping withthe 3D menu object is overwritten by the 3D menu object, and wherein auser cannot interact with the 3D menu object until it arrives at a finallocation in the virtual three-dimensional space, wherein the virtualthree-dimensional space is defined such that a plane, where there is noparallax between the first parallax image and the second parallax image,coincides with a display screen of the display device displaying theimage, and the module configured to display the control menu outputs theimage of the menu object of the control menu drawn with parallax whilemoving the object of the control menu from a viewpoint that is nearerthan the plane, where there is no parallax between the first parallaximage and the second parallax image, until the object reaches the planeand the menu object is displayed with no parallax at the final location.